Various types of solar energy converters have been developed for utilizing solar radiation to heat a liquid. For example, in U.S. Pat. No. 3,321,012 there is described a bank of contiguous semi-cylindrical reflectors respectively containing heat conductive tubular members through which a fluid to be heated is passed. The solar rays are thus concentrated on the tubular members so that relatively high temperatures can be achieved. Improved reflector geometries for better concentrating the radiation at the surface of the fluid conducting tubes are described in an article appearing at page 255 in Volume 17 of SOLAR ENERGY published in 1975 by Pergamon Press, which article is entitled PRINCIPLES OF CYLINDRICAL CONCENTRATORS FOR SOLAR ENERGY. Other types of solar heat absorbtion panels are well known in the art.
For those applications wherein relatively high temperatures of, for example, 400.degree. F. to 500.degree. F. and above are required and, in addition, substantial amounts of heat energy are also required, it has generally been necessary to mount the radiation collectors in such a manner that they follow the sun as it travels across the sky. The initial manufacturing and installation costs of such equipment is, therefore, extremely high wherefore such equipment has not been economically competitive with other available sources of heat.
It would be desirable, therefore, to provide a nontracking solar heat exchanger which can be used to raise the temperature of large quantities of a heat conducting fluid such, for example, as water, to temperatures of the order of 500.degree. F. Such a heat exchanger could then be used for many applications including domestic heating and air conditioning, power generation, solar pond regeneration and heating and sterilizing the water in swimming pools.
Swimming pools ordinarily are maintained in a relatively sterile condition by the addition thereto of chemicals. Many persons find such chemicals to be objectionable, but for economic reasons no better means has heretofor been found for purifying the water in swimming pools. Because it is necessary in many geographic areas continuously to heat the water in swimming pools to maintain the pool at a suitable temperature for swimming, it would be desirable to utilize the same heater which heats the water to also purify it, thereby obviating the use of noxious chemicals for purposes of water purification.